Optical instrument for observing surface engravings on optical lenses

Abstract

An optical instrument for facilitating the observation of surface engravings located on an optical lens includes a base housing having a light source therein for illuminating the optical lens. An image contrastor, selected based on the type of lens to be examined, is placed on the base housing over the light source. The image contrastor includes its own housing within which is positioned a viewing plate and a light diffuser. A screening pattern or coating is formed on the viewing plate to define a backdrop for examining the lens. A support member extends from the base housing and carries a magnifying lens. With this arrangement, an optical lens may be placed between the image contrastor and the magnifying lens to enhance the observation of engravings on the optical lens.

I claim: 
     
       1. An image contrastor comprising: a housing adapted to be positioned between a light source and a magnifying lens of an instrument used for observing engravings on an optical lens;   a viewing plate mounted in said housing;   a screen formed on said viewing plate for controlling an amount of light permitted to pass through the viewing plate; and   a light diffuser plate mounted in said housing juxtaposed said viewing plate.   
     
     
       2. The image contrastor according to claim 1, wherein said housing includes a first housing part having a first hole provided therein and a second housing part having a second hole provided therein, said second housing part being secured to said first housing part to capture said viewing plate and said light diffuser within said housing. 
     
     
       3. The image contrastor according to claim 1, further comprising: locating ribs provided in said housing, said viewing plate being positioned against said locating ribs to prevent radial shifting of said viewing plate within said housing. 
     
     
       4. An image contrastor comprising: a housing adapted to be positioned between a light source and a magnifying lens of an instrument used for observing engravings on an optical lens;   a viewing plate mounted in said housing;   a screen formed on said viewing plate for controlling an amount of light permitted to pass through the viewing plate; and   a plurality of resilient positioning members provided on said housing, said positioning members anally retaining said viewing plate within said housing.   
     
     
       5. An image contrastor comprising: a housing adapted to be positioned between a light source and a magnifying lens of an instrument used for observing engravings on an optical lens;   a viewing plate mounted in said housing;   a screen formed on said viewing plate for controlling an amount of light permitted to pass through the viewing plate, wherein said screen is opaque.   
     
     
       6. The image contrastor according to claim 5, wherein said housing includes a first housing part having a first hole provided therein and a second housing part having a second hole provided therein, said second housing part being secured to said first housing part to capture said viewing plate within said housing, said screen being aligned with, but smaller in size than, said first hole. 
     
     
       7. The image contrastor according claim 6, wherein said screen is circle in shape and has an associated diameter which is less than a diameter of the first hole, said viewing plate being transparent in a zone radially between said screen and said first hole. 
     
     
       8. The image contrastor according to claim 5, further comprising: locating ribs provided in said housing, said viewing plate being positioned against said locating ribs to prevent radial shifting of said viewing plate within said housing. 
     
     
       9. An image contrastor comprising: a housing adapted to be positioned between a light source and a magnifying lens of an instrument used for observing engravings on an optical lens;   a viewing plate mounted in said housing:   a screen formed on said viewing plate for controlling an amount of light permitted to pass through the viewing plate, wherein said screen comprises a dot pattern of apertures.   
     
     
       10. The image contrastor according to claim 9, wherein said dot pattern includes apertures spaced approximately 0.05 inches (1.2 mm) apart, each aperture having a diameter of approximately 0.02 inches (0.5 mm). 
     
     
       11. An optical instrument for facilitating the observation of surface engravings located on an optical lens, said instrument comprising: a base;   at least one light source mounted in said base;   an image contrastor including a housing, a viewing plate mounted in said housing and a screen formed on said viewing plate, said image contrastor being positioned on said base and over said at least one light source, with the screen controlling an amount of light permitted to pass through the viewing plate positioned on said base;   a support extending from said base; and   a magnifying lens secured to said support, wherein, when an optical lens is placed between said image contrastor and said magnifying lens and light from said at least one light source projects through the viewing plate of said image contrastor, engravings on the optical lens may be observed through said magnifying lens.   
     
     
       12. The optical instrument according to claim 11, further comprising: a light diffuser plate mounted in said housing juxtapose said viewing plate. 
     
     
       13. The optical instrument according to claim 12, wherein said housing includes a first housing part having a first hole provided therein and a second housing part having a second hole provided therein, said second housing part being secured to said first housing part to capture said viewing plate and said light diffuser within said housing. 
     
     
       14. The optical instrument according to claim 11, further comprising: locating ribs provided in said housing, said viewing plate being positioned against said locating ribs to prevent radial shifting of said viewing plate within said housing. 
     
     
       15. The optical instrument according to claim 11, further comprising: a plurality of resilient positioning members provided on said housing, said positioning members axially retaining said viewing plate within said housing. 
     
     
       16. The optical instrument according to claim 11, wherein said screen is opaque. 
     
     
       17. The optical instrument according to claim 16, wherein said housing includes a first housing part having a first hole provided therein and a second housing part having a second hole provided therein, said second housing part being secured to said first housing part to capture said viewing plate within said housing, said screen being aligned with, but smaller in size than, said first hole. 
     
     
       18. The optical instrument according claim 17, wherein said screen is circle in shape and has an associated diameter which is less than a diameter of the first hole, said viewing plate being transparent in a zone radially between said screen and said first hole. 
     
     
       19. The optical instrument according to claim 11, wherein said screen comprises a dot pattern of apertures. 
     
     
       20. The optical instrument according to claim 11, wherein said at least one light source comprises at least one fluorescent bulb. 
     
     
       21. The optical instrument according to claim 20, further comprising: a reflective surface located behind the at least one fluorescent bulb. 
     
     
       22. The optical instrument according to claim 11, wherein said base has a top surface formed with a recessed area for receiving said image contrastor. 
     
     
       23. A method of observing surface engravings located on an optical lens comprising: selecting a desired image contrastor, having a housing, a viewing plate mounted in the housing and a screen formed on said viewing plate, from a plurality of image contrastors depending upon the type of optical lens to be observed;   positioning the desired image contrastor in a recessed area formed in a base portion of an optical instrument;   illuminating a zone within the base portion below the viewing plate of said desired image contrastor;   positioning the optical lens to be observed between the desired image contrastor and a magnifying lens supported in spaced relationship from the recessed area; and   repositioning the optical lens relative to the magnifying lens and the desired image contrastor, while viewing the optical lens through the magnifying lens, in order to observe surface engravings on the optical lens.